The antis have great scepticism about pro-helmet studies because so many are bad - note that ALL the scientifically trained people posting on this issue are anti's. In particular, the famous 85% benefit study was so poorly conducted that the careers of the researchers would literally have been over if they were physicists or biologists. Yet this study is still widely quoted in "meta-analyses" that purport to show helmet benefits. Non-junk pro-helmet studies are pretty much non-existent.

And, in general, arguing that people have to be prejudiced because they think the evidence on one side of an argument is stronger than the other, frankly, extremely silly. Lots of arguments are such that the sanity rests entirely with one side: neither Barak Obama or George Bush is not an alien, perpetual motion machines don't work, the Holocaust really happened - and a beer cooler hat won't protect you if a ton of metal hits you at 30mph. (However, one of the new - and very expensive - anti-rotational designs MIGHT have a measurable benefit if it has a strong enough shell.)

As I've said before, when I started researching this issue I expected the best helmets to be reasonably effective - I didn't set out with the urge to prove that it was pointless to wear a helmet at all, just to find out which helmet to buy. Any bias I had was pro-helmet, but the evidence shows that for general use they make little to no contribution to safety.